SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '773ce3810793f2fd715444975ee56f7d83aa2b38108d65010222323e7fc2c4c6' 
  AND token = '596+wJjBnM4iDjVBcf/4PgzmhRmmJwvMh7N6BV5zLe0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}