SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '712cc5397b14016f6c96a8cae6079420158a4c6d62a7ad5595b7038bbf004943' 
  AND token = 'QjFbs5FqwVQHPPswkYSgIhI95mhC2NWUHgt1zaZyjpQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}