SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2b73ba3f7ed6f2720f360e19428a49bd8b1ad6e037474e47e1e81db072c6add0' 
  AND token = 'Hq1dOJfZfwNwis0jANfERv6cJzJsKE/17lpTfTpMVws=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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