SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '640a374f44a302cf5e37f87bccbe98113ecb2c6050e314d5f5bc1842e4e1389b' 
  AND token = 'IDF39G03GCisW0Due0aBaQnFHwn61xxKjQLOFAqn/Yk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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