SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ecd7ae6a091016f21bfd4dae67e146413a1629d9ed34a61ae20190ada39ddfcf' 
  AND token = 'ra1Z20ZE+ks+6+Uo8v++7Q26PKQzMkHXZh+aLZGjUZA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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