SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '10f6be8f9bc4a7cd596a9d1cad02fe9f07baaa82aebbf3a549514de3654b2bbd' 
  AND token = '+CGf3kPwZXztqcRrBpvXHXErjqRBCRs9x6eYMycKZVE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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