SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '551d876d60164302fb2c80332081b5d3b1c8f081521728e94d50116dcd69cb2c' 
  AND token = 'bLzIyPG2sBqG0gxiXwLtineEWsQbYWZV+QIrA1UZMzE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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