SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '30c69f35e2783c265513ea431bc7c38f910cfaabf16cf8311b24e9fbc46634ed' 
  AND token = 'U256O7da2Btxg+RpSl8UPm+Hxi8iCBDlaLTOdGimHjM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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