SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a68e71d23c03413340a0c15fda5275507d6fea9d5d77b814915fc595078fbc70' 
  AND token = 'HoKKFhcSIcDOsKj8EFGnCKL5g54vwJ+CtaUgPWkBYmI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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