SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b02de159c22bac35d2baf0a8f100603c4806ef0802b66cef30b6f1b37e8703d4' 
  AND token = 'nvzCg+cHYBn84X1quhdUm36VC5dZseLx+weitMArlZg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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