SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c3cdafa76078d7abbccd2fae2d2b1c1500fdaf8ee652d57eba11a115bcca5462' 
  AND token = 'FvKjwkhYF8KwiSkPjUAjdBwhhlBD0lCZMdFfXe7pdBk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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