SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9e520eeaeb648075679f4ced302807790276776cdb948b30db3b774b71c441b0' 
  AND token = 'frUbWnNJ0jDkqETQLiKT7Drdw3c+ShnKuFczWnNyNKk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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