SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6c0502054decbcc37fbc3fc56fe32b28178faddce1129959204ab3a314d5f761' 
  AND token = 'ZCNW+MnBt1zqDTjzcRJqX/v8DW0CrSJ+oPDEs+GmeKQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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