SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b938224e81d3e1b4586c7b50ec37d22cbca143f64715ab0b4eb681bacd9ff197' 
  AND token = 'k4ZBbjlGkdkRfZkzHXDo48lge7hPC4uOiOHZJ5VwnmU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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