SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '57a325bed0d6e965e978238c71d106e73b2ab69f8e73f48151034b0ede518955' 
  AND token = '/oBQ1ozQYwvMWW62F4jAq/CWcMrfu/tsLnKBaPFhhHg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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