SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd4a8fe9ad9cb0fd875f6fdcd73cab6feb1561d62a00c2391cb66a02f52313de2' 
  AND token = 'NAypFOYWpwVcLH/lAVd6mb4IW1tEE2+tNNrWVbHPVe4=' 
  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"
    }
  }
}