SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b2c11786002727963b57c9b3e9d1cf878f5662efbccdfb51fa4452ed0b8bfe92' 
  AND token = '1hqhcpGU8BEj5F0QSYripdnd5K99zszJV2B7xJov+yo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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