SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '587d52c74b9fa79371b2ec34a77d515c2bdfe2b56e92c80fe5d6b6eaab9b688c' 
  AND token = 'gbAWOYmjUa+TWAvflU7mXH+V1jUx4+gXsww+1uFYgYs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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