SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '869327ee9ef83ea07008907168df73d1e4e89e1b4d1bd93ec74027190dfe929c' 
  AND token = 'kLtfNLHUHZTIjDLBEBHt7Apgu5LW1IWWB/uyzDV/djs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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