SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '87f3d59234fccbd299ace46cab28b393467d66b6190a85768822734736feb68a' 
  AND token = '7ga7eEJ0bQcBN2zcL9EGP4/Gtjsqbhg2qseoOwFjrrQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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