SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd2478a350cfd79b4a46baeb6e53b1f9a63887101a70c94776c6270f17751e0c0' 
  AND token = 'KJdlP+CZLMvrY2LfFWBfUorl2tFXZZejh5I/fCpB/nI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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