SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '90ad9458227a884a66f4eb312ff434284d417b6da51906c57d2dd06d5d63f312' 
  AND token = 'AEbHmYd6Mr7pz+sFESJ/zl7PGfxMQzslFvBwCJ/x71U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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