SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '96e23b7ef908115ff6dfdb723c65e738ce4ccc6e1d455cb3be45823bac275c7c' 
  AND token = 'HnQIwjjOIxhjXV831Mk1cThPBjzNmYZvbxc/UycE24s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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