SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5fe2f630955db91807bf9bae0fa5360f6d47a619368af74d24347f15034c3e9c' 
  AND token = 'T94oKrFeVcSdgRkLKZayuUzx/W2ytjYQn1KBhksv7pM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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