SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a79efd7ed732e1184266e09534e7b8cd1a3cf9166151b5a517b1c145f16b3cd1' 
  AND token = '0jM0nsPQpcthoNmp9Rdl8plUunOoV25bPuQ7SAMXL+8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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