SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5ce647d3ab033e341d33499d5bfd207d83e5f5e1a2bf5cde608af7a47a104ea1' 
  AND token = 'DLEojidPONiZGdn7NTIo4Z91aqNU8BqTRY2yI1Xmnm4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}