SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '37e30afd76416b2a44e50eb7d99d298196eb5d0f70c44ac74630273871b9a1a0' 
  AND token = 'ry20a29UADkFcLDT8fRCsF6Q8HXvMmOog0hwT+mlpSY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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