SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ba2ca1adebf497e5490ef24d47b9cbc1f68a51b63b7ce92762648af3894a4b2f' 
  AND token = 'JcQshMzMEtnROovD3lEjHXiPYwK4xHVAZvy1I4r5MLs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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