SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c00fa5fd3bcce5640cc42cea6af02954cf13f5d17a6635ce61bb10f5a3993f15' 
  AND token = 'g6LSzodB2B95Janhx69zHVzJUlXtddvRpbifRwsbzzQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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