SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1b842dade462d75b15ee42c54455a9f587abed2b0a2145cd693dfe1260732198' 
  AND token = 'mQEnhkLNyst4uuee7Ln/eSstQMTtZ8pK75qpNm2fwUQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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