SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '52e349c35db593a2e6962a76ca873db81e680a13a105b9fefc766dcd10889a80' 
  AND token = 'mMTinqwLpkrmkdab6dkHKLlPWWImE8uYDe2lhwURqlQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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