SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '237c173182825504c3f95d00b8df845ddd46573b763301fabf3218a4987091a4' 
  AND token = 'pBSYN6uWQwuC1KA6NpS6BnMJRZ4wcETfSCxW5MNu8zQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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