SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3625fb76b798e2f9ec6fae17154d2b769aee7f9c3374cc602fbca24000dd8ec8' 
  AND token = 'e3WpdZKaDyB3wHP/7duqhvPIhx32gwa5hxgtt8KZ8dI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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