SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2de619ff99d280ab2fa56782ab6861ab9950aac87246b9b9a070366ee31fda0f' 
  AND token = 'hfPABdV+pf5jbs6YlGnd7OpheysO/ALc9ep1UtsmzD4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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