SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5e85bc358a6986c6f267c889b4370e044dfcd2e88bf99e0389d4f39e9653af6c' 
  AND token = '/GH2uxQKSgW+q/+yeG1pXPq5tr0vgEjV3jDJJx2du4Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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