SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3fcd12343927027448a7a1ff8d2c02ff109683f6450f946862b8ab8a0dbd9eb2' 
  AND token = 'mwjPn7ChG/ZYjzPdTrWFrCbq8gQG+0y9lU9hBIh0nac=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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