SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5c6ddcb955f15a55330a2443b51920aab64b3cf6958d829e6691c02c1cd732fb' 
  AND token = 'YeI1SpmAwqD0Ig3EvAaeWTtskN6VwK7p4dg+YaBzzr4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00013

JSON explain

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