SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7828cb6f99e98153e188798368af23f19d3760b6a75235a90e02f8629f93eb7d' 
  AND token = 'GjSsjoMDSOU4F70ovBVnaGZAS+oyKoyiqnWhHxWdHkY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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