SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b30270bfa4dada6e961c3ab7593a5994bee9d2573e4a63b9a8b0844ab823dc62' 
  AND token = 'PzSKz1RQD9QWiXf2K1ExzeJCraVK8EwpmGHCLz9VLpk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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