SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5aeb6cd4f7aa2797170a6820f38fcfba3c7dc82fd1c58a383acda3bc44e5c402' 
  AND token = '7tCORVwpPAGwPBGt0lj2I6dnGQTIZTfMh48sf58USUc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00070

JSON explain

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