SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f35b37190ddef34760e9eb49ec2c03ebdf5d2887185df222de1d6fad96ca8a59' 
  AND token = 'mH1R5lpw+j/fMkyXCkl1fB7H8t9l2N4v9LSyUeYGlTM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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