SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a068572aa154485d59f41ef78234b076f24a03dff6d347102e2766dbe7773323' 
  AND token = 'NZBcJ0vOqOE5wRJ2zkWCaHRyTsRQYayemNsQk+x6RMs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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