SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '71f573d78ba8570dc8ad09b68da1d7705aed551c8169444c2c631df48e5e0f5d' 
  AND token = '0a13I41HFuRJqH6ymQyxDruaLRypN63rQDrF9tcgWsY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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