SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3cf72ab4b424f8ffd4d47b7ae31c635f27a6189d1773c66521d7883141a21345' 
  AND token = 'Bvee8sVXy+aJxZTbQ1gg3wXuL3fhbX3ZcvPmqYvXQIw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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