SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '697d6fe56c42fc8f34512c748950665e35705278f6d18d213b8153c67825cb2d' 
  AND token = 'YdhAsBsls6zhkL23sc0qo+UETbuYmrQ7VCXy7JBEICo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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