SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2f15715da940067ee9645cf19236e86c68fdafe1927863c8b1f69f84167643d1' 
  AND token = 'gCaNRzTUzaVKQuJtRpL0JwHJwSEtI5luneMD9cHpTHM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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