SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f7c43db5fd8b88eb8dc1240af9d28d3accbcaa5a6a7a601ef0eaac279db8022a' 
  AND token = 'jsdteFuu89PGi0OtVpbfDWP1lAVM4daukBeVjresWnc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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