SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cb96504d50767c9f575dfc1974f69764773c32ce52a047ce4f5ce674b24d4dc5' 
  AND token = 'UpP4nPNxH4YHPcMNbPKKJy163AbuG/UxCwRX0Xg54aM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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