SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e44d202b7e106dad8ea6f9c6956f58052c93d4197875e474c83cb2712eb92572' 
  AND token = '/elsRcNgwowUvaGvUkbxXM6SWiIpCjVdCtDaMre784o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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