SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fec78084d582f84c05d6b42f93373ea116aea98d928677d5a5971020cfafa856' 
  AND token = '68Fi6TiGUKpJX3rLmf3/h+LVK4N7irVu7gMCMQZmGXk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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