SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '458039fbab7b79bc16f422b598740bc94497b8260f27efc41420d23f5da756e8' 
  AND token = 'XEvFq/0xLSgjAFujMoFGHiH+rGenZanIyVwxLpbg5iw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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