SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a626fba1c8884a09a7747b0f46d72ce091087805f4686013449e01e5597c7023' 
  AND token = 'iENtlnSj9uz1VQEdKs+s9HwZVcK9ztkwsn2IjfXMB50=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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