SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '44b6c3df82648b78d1054ddb6540222d487eeee7b641fd421527173464270cbe' 
  AND token = 'lPwUk+5W1vUfAJu0KjHtmOSzAxIaRFD39rUupVGLj2U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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