SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd3cbbc6854051b789e5a57d2cba627ef54078e2dfa9bfd732d3f338d50131fd0' 
  AND token = 'rxMO6PXAyZf1YF/eKQmBEDnFCk7++tOXBveJlsu9pzU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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