SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8f171daa8336dfe1134a2ecc819145b74b6462d9c8173da53d02b28aac57da6a' 
  AND token = 'Ke7nm+Wngm4xjDLjP3y8gfUWQKH1HDUDd3jKfgXeYW0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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