SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f753a4125cfb65077ccb7a1c453e9d492b7000071acfb0f8576ba884303165a0' 
  AND token = 'eHYedvc+SkcBTjrlqZEX6ufG1vggJoz0dYZKXVv2En0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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