SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ff549f2d5ea55008cdfabd738cd78e726d5c649bed1a7aa7c7154ac2943eb7b1' 
  AND token = 'alfwm28JRlqNyEnm/BCHi3iJaiBOBZWnr5tgEWu+itk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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