SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9343b5d868afc7ab52febb9579b12aaf002dfb9944285a8ce6da79c0d7633aed' 
  AND token = 'QpRPXCWysV+xsQSdtgTIebSFmB5IAAbZyw2vkn7FrBY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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