SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0012b7647f14ea45eb39fd9425de4390a0319361014dddcf2c4a25ef2cf9d1d3' 
  AND token = 'KM4Gh9CleOpik5NqRvsDq9pdZcpQ7AuO/MNjwojhX/w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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