SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9a830a7356f234c70dfd8c68fb57fa752866abaff8cd01b5c1869aefdf9c0c64' 
  AND token = 'aPCXClUJFvcKbCwW4ol33t9+QtUsNKMYwDl8SN2nH5Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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