SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5a9d35ee004c3bfb751dfec82ec1569db1075212ab2c87ca7412c8a6e7d20568' 
  AND token = 'k6/TDDc7qSQqaXrwrdWJranh4M9VzPupv9ddLqZR6Sg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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