SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '846f741a7852f7c7c3a4b9a79862217f97ebcd0be71bcd0691d2e80fa3ce3268' 
  AND token = 'KWkfKC+4uqHoTHvimjlKOJjng6M7BMRUN5X5U2Gov3M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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