SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ae255c784be58b2d3376e3e33a4909c8b82b1f37e345f68c077a890d9efdc66d' 
  AND token = 'ci0YHVhrkzF9LgqB80T0zyjJGJTRWhOboolFouKRnwo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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