SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '055c76644d83e2284275b6a183c42dd1b22047c2920a31f17a59829159e05f77' 
  AND token = 'pRm8sPXBQmZVstRLujczVO13GJmsu/6Zyxo5lHXz+jM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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