SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e80a08c5a6596241f07d2c482e5a89145231ef14a8c039e61db71e3856f77d03' 
  AND token = 'C/slBPF1iUR49xM8QX2YvpRFK8VWM1G1dnT9jmJwkok=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00059

JSON explain

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