SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7bba134167fd25faf2352c2462d60fc5e1a1c5dc12b0881e195b22e8221cdc43' 
  AND token = 'BlM3jidHoIxBLcnDP5NlfjqAgtGCx8bqHZMrxy+7N4g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00091

JSON explain

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