SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '12e7d810e0789c29d70993b44816f980baa5f6506363a4ec2997b525f3a99578' 
  AND token = 'fTjYXJcm0M8/dx+wt48mDVITHxGPsQ4K+LUfwuq2AbM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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