SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '17c931ccedb89dda488ff20d5d689afe3999e0d0a2c5f86222222145165dd32f' 
  AND token = 'UEH0hEvie48PVO99hbS5Dn0vAMN5IWIW2Jg3nol50rA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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