SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b572ab3cdabd1062b6942f73dac3c365fd960c390308b604d9ec51509e81cba5' 
  AND token = 'tXgaSFqJkXS+BOYay+SNpAJAdZBV2Cwbld4wGQfPEaM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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