SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cbf497b596a8299a818a9015dd49e30e6f136ef92d611f1a0a659c135b375c51' 
  AND token = 'xjIQNWZ1SxvB1bx5ux7Tr3sObWtSabZbJZ9lJFlVXog=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}