SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '098c0513b819084570c22a4963afca56c797f991a9677d17ce81d9518c10c2b7' 
  AND token = 'v7eOdZq23DwfDdErCVAY40ln9cCvZ7mJhhvtQ74JBvI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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