SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8967b61846181d093265a7926c218468fa8f39a86b4ccec52d42458bdad73b37' 
  AND token = 'vfh0b8acdwocDzcW5XcMnX3soNwVPkU3u6ZL2VNHzpM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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