SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'abfb461aa62cfa0c90483d3b7724d5b14b1e566e14d6c0d1094dadfe0a876117' 
  AND token = 'MzzjaYPFCmTH7GJWHFAAm7n0YEnVrcoe8qZmjvXo7E4=' 
  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"
    }
  }
}