SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '683bc5352cfa03cb1dee6698581126066403ada9a39c1fb65f9aa4ddcbc235ae' 
  AND token = 'sVClFrpEqbveWY7MbBNeH8GFmQlJZgALGHDxgcsowWo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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