SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ef2321d418f9ba6a26577946764c1f7354f148ab07d69724c80841c062733fe6' 
  AND token = '5woV/hFVTyeU9gLZil/INBt1Xn8e/1vM0zLse3JpJKw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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