SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd799926b5c2eb95e14cd756fd90ec398624884336edaf53144122179bd01f8f9' 
  AND token = 'JJWk5SqfS5kZcPpUEkbas20vh58waAy9YCwxclscfJ8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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