SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '96d494fa03e47451195624daed23501c83dcf3c8bd4e70cf36d82dc35adaa42f' 
  AND token = 'MrvTlnV/HEmh0dJl5F2qlJhlUdKDBC3yEIQCv5NUvJQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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