SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e3adaef7f1a061561979ea5ef9039254b68a9bd8e3bb6450a988c4f58acf10c8' 
  AND token = 'oKVhc3tpOfXtdr6tUs213k6HGgIhANUVZNEQEOwllio=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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