SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd642cb8c4166168ed12f644fe7d5f56fcb63422765c6a6f79826e39602a2d21f' 
  AND token = 'Hq0vgCBNss3i0o+TszLUwzOjZCXyTgocoV4tGuD+Uk4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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