SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4ff02be2fbc6eb76b2df7ee393ae0c494fc946d0a3369d61d75865f4e8aabe08' 
  AND token = 'dlPjAvgx8MGjTZ6v2q2NquC7g9yJvWowXobqj0GAg0U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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