SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5a30e4b60aacc4a0216b22aa19213f73f69a398536aa055b3e8fba138449ffe6' 
  AND token = 'hvt1ApjlRKGkyImPKSpHtlYIFcm1CbHe4fVtGFrudC8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}