SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4c2f52f12ada909063870061fd17e8361cceb6e1bf110e2b3c71391a3e75b9b2' 
  AND token = 'S+thME+RSaTC+VGUWq3TzfUyQw5IJf7JRSbfhXa2Bx8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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