SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '974f0822215ccb3c41b8474b3b6998b8bbc9066afd3ac8e30007df3fd74ca0c5' 
  AND token = 'QyJxL7luX7n8bXSY8bkWKNqj/bRuCUPfBHWLF/5FNbI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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