SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3afa848314839957c6fa48247b36b3f489a75354629af733dd7f2f2ced434de5' 
  AND token = 'iNwyWrqvDSfi97AKB1c8GkgSwIA9dOinwctlnqSJEPE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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