SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9b157d0884374dd3eda0bebac69bbee918530c735fb972b35c3af1967cabe543' 
  AND token = 'VSkslIzUVc8qvc8KjEBaOxIVPMAIy+OXRB72ksXq/Ng=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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