SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '98018ecc3a323a6c9b44661cb517661360b84d57ed1191f5058ddd2686ce0e86' 
  AND token = 's4BEc/NVW8PzqCLssmeTJPFbruyuaAK59DRSc72jMNU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}