SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cf6527063adc743cb4e78825989c0d7a3c6148a5fd0f90791a9d33701295bc12' 
  AND token = 'fFHVlJSvEmXQfVF3pIlYN1hovwnzb7KEjPFdyUiTJaA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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