SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '87f84a96ae152838905b6f95c0505f6e379941d9bceff933dca77dee2f1e8fda' 
  AND token = 'VxCXPhI+qjYkiXQSAtddVPiqm03FugVMmHt6u4JBlyU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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