SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'aeb61c41f583d4fb575bfc85241d127b17a3f7d708d4bc2230fa8581bf053416' 
  AND token = '4aYmIm1wuVER/vhgRDgC/YUpQqFlaGQopSXMXyGCyF8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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