SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '94da00fe11b0752dd900e40ad02fdf33c274439ad66a3f7282b444933677a273' 
  AND token = 'g4JJBIvc/ULHSsVzZyHcwnpFVwPkOF05Z8VV+zpFJPQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}