SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2fdf541ca876e36431b212e76235d157f0257dd035da796880dd398fe47e1784' 
  AND token = '9bX5ZbVKfBKBoNgeSpRHiur61UTa6hxPfAhPvX41DGU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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