SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '35301b6bdd2593c6a9c6e365f258ef34df0edb8e4fe0efdb41edc914ee91c912' 
  AND token = 'hj6qMZ4aqSxHKHGJoN/QBlZWOGTSjOJW9FK5t7Bx/zM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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