SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ab962c926557cac7eaa09c4eadc6e8b4d24fbb19700df579b86d6bfd3dcedb71' 
  AND token = 'QrvmdnI4d3ItxQSGQxSRTrqHz/+8shXoizI/C9cTZ9w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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