SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '21a0218bcdfba1d80ef3c44bdaad9c3d5eac17c5890c19f85a0a76ddb0317aed' 
  AND token = 'w5t0kvIAHEasWc4Mh60eiIUvi83wl4yXXvALIzqHf8g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00080

JSON explain

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