SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '87e2f1f6c3b5d39dc15fffcf847ac958a9443d221ba88fd1fdbe5fa3bd4bf111' 
  AND token = '5UoCJZrsEOoCZtByNgKbVMqKATGqattWKC/AJ7lL4xg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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