SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c7f8bd2e9f5e82280d240a25da23afc2663a743490f196cb6030c4a19c5e619c' 
  AND token = 'uIopObzWjeiupfSiOUyGTbq9+UvYJh8gl0zVYxNie38=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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