SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'e107ccba1ddd5155bd9bdf268bdb20907cacd852bd08b6ed818f369fe84b80b4' 
  AND token = 'MM4AlRVo9hGG4p2uBUYhkJnP7msq5+eTlBwhHvQgoNo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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