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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ebcefe5291de474e12f4839e5eb18a5054644828e8bbf16fde4df8989bec0d3f' 
  AND token = '8BERdPRB4ZjsfXHed/nNsqpwA5tHXhlLM+lQ2eBPDXM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}