SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '20362b41b5004934ba00e65600519e6b3439b922571d4d17b5f6e7f89dee280b' 
  AND token = 'G9uiqIHA1yFKCGxiutycHE/FwGGJ/buhJvZ+jTEcLDE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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