SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3492f62f1f7b0b13f6bd951f7697e197e7cac2e8473225954f201aebffb8aecf' 
  AND token = 'oXWS8ziityQqzmVoQDGzrKiL14+9HiGAIaWRFmi1Ins=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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