SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '85d68424bbddc2849b0e4a2520443a68b32469269ed0bfdc5054aca111dd2f8b' 
  AND token = 'wFBaUCXSm+bCMJkMHAr9bVbV33GFPDYbF+wySDow4+U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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