SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '460cfe67e9024ba5fd7cabd5f3dd337494a837352a76932e6bcecab412541e35' 
  AND token = 'kXr/gXGszZA+EVjxm9jg/6Robz3t0W5CBGvPNxoB/5c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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