SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e8043f09d5d00065740eee40637c44c27899d54a1d12f3090be1e973a236fa0a' 
  AND token = 'J3b9QtjsBeEo+niUZpq4oFynrmrRTIz7knLnGs0qyHo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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