SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f9af25cb9579014938b6ed02a1f8390f400042e64a69773447feb10f1fc497ad' 
  AND token = 'NXAqgOGCi2em/794nLBgZh7QJvdiCasMshGFV6+cD4I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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