SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f83dc25a7dd9416238083246935023cc2229542b26604d317c02d9c830d0ad80' 
  AND token = 'DPV0qBJGgx9FHA8jXBqTQohpwBIsZwjsu7VCMrxH8wc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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