SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e510698dbefed2000b3f44c574d3cb8e37d32cb571fdd33165f20eaaefd09144' 
  AND token = 'BiVtD/qWP7VAqQbUWF1rumGV1N2XYcetfYLx3qfI16o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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