SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c9d51bcc360066ef037ae8687fd36b8f0fd1a7e21db7f471d0510cbc6820c803' 
  AND token = 'PuIT3Y5b3bBQgvjQNrRMNTPjYAkzBi5ERwbnUjRbjIM=' 
  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"
    }
  }
}