SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '946b902e893c92c2461e3df1546f7a7fe1981ae1aeb059d44db18252cc1f0df0' 
  AND token = 'JQ1QVA6gIdnaPOcnuw0YgB/hHZdl989zLnHsvUHnJyM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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