SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9dc68d57dafaf41ab5a4330bd5536bd107148b32913ab42c5d0a935396962ebe' 
  AND token = 'rL4zmdHher6KFtk/r5TymvG+A+Ku3fFNyCyJZY5wlZQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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